This driver utilizes the methods introduced in a previous
patch titled - "ACPI: Introduce CPU performance controls using CPPC"
and enables usage with existing CPUFreq governors.
Signed-off-by: Ashwin Chaugule <ashwin.chaugule@xxxxxxxxxx>
Reviewed-by: Al Stone <al.stone@xxxxxxxxxx>
---
drivers/cpufreq/Kconfig.arm | 17 ++++
drivers/cpufreq/Makefile | 2 +
drivers/cpufreq/cppc_cpufreq.c | 176 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 195 insertions(+)
create mode 100644 drivers/cpufreq/cppc_cpufreq.c
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index cc8a71c..e8bb41b 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -261,3 +261,20 @@ config ARM_PXA2xx_CPUFREQ
This add the CPUFreq driver support for Intel PXA2xx SOCs.
If in doubt, say N.
+
+config ACPI_CPPC_CPUFREQ
+ tristate "CPUFreq driver based on the ACPI CPPC spec"
+ depends on ACPI
+ select ACPI_CPPC_LIB
+ default n
+ help
+ This adds a CPUFreq driver which uses CPPC methods
+ as described in the ACPIv5.1 spec. CPPC stands for
+ Collaborative Processor Performance Controls. It
+ is based on an abstract continuous scale of CPU
+ performance values which allows the remote power
+ processor to flexibly optimize for power and
+ performance. CPPC relies on power management firmware
+ support for its operation.
+
+ If in doubt, say N.
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 2169bf7..676660e 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -78,6 +78,8 @@ obj-$(CONFIG_ARM_SA1110_CPUFREQ) += sa1110-cpufreq.o
obj-$(CONFIG_ARM_SPEAR_CPUFREQ) += spear-cpufreq.o
obj-$(CONFIG_ARM_TEGRA_CPUFREQ) += tegra-cpufreq.o
obj-$(CONFIG_ARM_VEXPRESS_SPC_CPUFREQ) += vexpress-spc-cpufreq.o
+obj-$(CONFIG_ACPI_CPPC_CPUFREQ) += cppc_cpufreq.o
+
##################################################################################
# PowerPC platform drivers
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
new file mode 100644
index 0000000..93c219f
--- /dev/null
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -0,0 +1,176 @@
+/*
+ * CPPC (Collaborative Processor Performance Control) driver for
+ * interfacing with the CPUfreq layer and governors. See
+ * cppc_acpi.c for CPPC specific methods.
+ *
+ * (C) Copyright 2014, 2015 Linaro Ltd.
+ * Author: Ashwin Chaugule <ashwin.chaugule@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+
+#define pr_fmt(fmt) "CPPC Cpufreq:" fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/vmalloc.h>
+
+#include <acpi/cppc_acpi.h>
+
+/*
+ * These structs contain information parsed from per CPU
+ * ACPI _CPC structures.
+ * e.g. For each CPU the highest, lowest supported
+ * performance capabilities, desired performance level
+ * requested etc.
+ */
+static struct cpudata **all_cpu_data;
+
+static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
+ unsigned int target_freq,
+ unsigned int relation)
+{
+ struct cpudata *cpu;
+ struct cpufreq_freqs freqs;
+ int ret = 0;
+
+ cpu = all_cpu_data[policy->cpu];
+
+ cpu->perf_ctrls.desired_perf = target_freq;
+ freqs.old = policy->cur;
+ freqs.new = target_freq;
+
+ cpufreq_freq_transition_begin(policy, &freqs);
+ ret = cppc_set_perf(cpu->cpu, &cpu->perf_ctrls);
+ cpufreq_freq_transition_end(policy, &freqs, ret != 0);
+
+ if (ret)
+ pr_debug("Failed to set target on CPU:%d. ret:%d\n",
+ cpu->cpu, ret);
+
+ return ret;
+}
+
+static int cppc_verify_policy(struct cpufreq_policy *policy)
+{
+ cpufreq_verify_within_cpu_limits(policy);
+ return 0;
+}
+
+static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
+{
+ int cpu_num = policy->cpu;
+ struct cpudata *cpu = all_cpu_data[cpu_num];
+ int ret;
+
+ cpu->perf_ctrls.desired_perf = cpu->perf_caps.lowest_perf;
+
+ ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
+ if (ret)
+ pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
+ cpu->perf_caps.lowest_perf, cpu_num, ret);
+}
+
+static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+ struct cpudata *cpu;
+ unsigned int cpu_num = policy->cpu;
+ int ret = 0;
+
+ cpu = all_cpu_data[policy->cpu];
+
+ cpu->cpu = cpu_num;
+ ret = cppc_get_perf_caps(policy->cpu, &cpu->perf_caps);
+
+ if (ret) {
+ pr_debug("Err reading CPU%d perf capabilities. ret:%d\n",
+ cpu_num, ret);
+ return ret;
+ }
+
+ policy->min = cpu->perf_caps.lowest_perf;
+ policy->max = cpu->perf_caps.highest_perf;
+ policy->cpuinfo.min_freq = policy->min;
+ policy->cpuinfo.max_freq = policy->max;
+
+ if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)
+ cpumask_copy(policy->cpus, cpu->shared_cpu_map);
+ else {
+ /* Support only SW_ANY for now. */
+ pr_debug("Unsupported CPU co-ord type\n");
+ return -EFAULT;
+ }
+
+ cpumask_set_cpu(policy->cpu, policy->cpus);
+ cpu->cur_policy = policy;
+
+ /* Set policy->cur to max now. The governors will adjust later. */
+ policy->cur = cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
+
+ ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
+ if (ret)
+ pr_debug("Err setting perf value:%d on CPU:%d. ret:%d\n",
+ cpu->perf_caps.highest_perf, cpu_num, ret);
+
+ return ret;
+}
+
+static struct cpufreq_driver cppc_cpufreq_driver = {
+ .flags = CPUFREQ_CONST_LOOPS,
+ .verify = cppc_verify_policy,
+ .target = cppc_cpufreq_set_target,
+ .init = cppc_cpufreq_cpu_init,
+ .stop_cpu = cppc_cpufreq_stop_cpu,
+ .name = "cppc_cpufreq",
+};
+
+static int __init cppc_cpufreq_init(void)
+{
+ int i, ret = 0;
+ struct cpudata *cpu;
+
+ if (acpi_disabled)
+ return -ENODEV;
+
+ all_cpu_data = kzalloc(sizeof(void *) * num_possible_cpus(), GFP_KERNEL);
+ if (!all_cpu_data)
+ return -ENOMEM;
+
+ for_each_possible_cpu(i) {
+ all_cpu_data[i] = kzalloc(sizeof(struct cpudata), GFP_KERNEL);
+ if (!all_cpu_data[i])
+ goto out;
+
+ cpu = all_cpu_data[i];
+ if (!zalloc_cpumask_var(&cpu->shared_cpu_map, GFP_KERNEL))
+ goto out;
+ }
+
+ ret = acpi_get_psd_map(all_cpu_data);
+ if (ret) {
+ pr_debug("Error parsing PSD data. Aborting cpufreq registration.\n");
+ goto out;
+ }
+
+ ret = cpufreq_register_driver(&cppc_cpufreq_driver);
+ if (ret)
+ goto out;
+
+ return ret;
+
+out:
+ for_each_possible_cpu(i)
+ if (all_cpu_data[i])
+ kfree(all_cpu_data[i]);
+
+ kfree(all_cpu_data);
+ return -ENODEV;
+}
+
+late_initcall(cppc_cpufreq_init);
--
1.9.1
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